You Cannot Trade With ______

well...no idea...seems fine from my side...was able to see the offer a trade option and all...just the trading portion never did seem to load. should be some problem with steam.

have you been using a new computer? or has the SteamGuard popped up at login? Happend to me once while using browser at work

i am having the same issue. same pc from 2 years, same steam client.. no restrictions.. nothing. There was a steam client update and after that m having this issue. :s

How long have you had steamguard activated? Needs 15+ days. When i was trading with someone, he had this problem.

You changed your password in the past 5 days? , because steam did that if you change password , you can't trade for 5 days

this is a bug. this is the solution -

Open up a Web Browser such as Google Chrome, and open up http://steamcommunity.com/chat/ (Chat from Browser Window basically).
LEAVE THE WINDOW OPEN, and go back to your Steam-Client Window, and send a trade request.